The present invention relates to a suspended ceiling system and more particularly concerns a suspended ceiling system and an improved connector clip for the runners of the system.
Suspended ceiling systems are extensively used throughout the construction industry, both in new building construction and in the renovation of older buildings. This type of ceiling consists of a grid-like supporting base which is suspended from the true ceiling and which supports a number of ceiling panels, typically of acoustical tile. This suspended grid also may serve as a support base for lighting fixtures and heating and air-conditioning outlet ducts.
The supporting grid itself is formed by two sets of beams joined together at right angles to one another, with main runners extending in a first direction and cross runners extending in a perpendicular directions. The main runners consist of long beam segments parallel to one another, each typically extending across the length of the ceiling. Where this distance is longer than the individual length of a beam segment a number of such segments may be butt-spliced together to create one continuous longitudinal beam. In contrast, the cross runners, which are also parallel to one another, form discontinuous beams extending perpendicular to the main runners and each typically spans only the distance between a pair of adjacent main runners. The grid system thus formed is suspended from the true ceiling by wires or equivalent means attached to the main runners.
Several different systems for the attachment of the cross runners to the main runners are known to the art. They can generally be divided into two groups, the unitary connectors and the separate or piece connectors. Unitary connectors have the connector pieces integrally formed as a part of a cross runner. Such a construction is shown in U.S. Pat. No. 3,979,874 to Cubbler, Jr., et al. The end portions of the cross runners are provided with vertical tabs which are inserted into slots formed in the web portion of the main runners. U.S. Pat. No. 3,565,474 to Stumbo, et al and U.S. Pat. No. 4,161,856 to Brown, et al, are similar, with both providing tongues which project from the ends of the cross members. In Stumbo, et al the tongue is integrally formed with the beam webbing, while Brown, et al provide rivets for the attachment of the tongue portion.
A variety of separate connector pieces are also disclosed in the prior art. U.S. Pat. No. 3,385,021 to Nys provides a connecting plate that is received by grooves in the cross member flanges. The plate is provided with a projecting member which is received by a slot in the main runner. U.S. Pat. No. 3,093,221 to Purdy provides a connecting plate that clips to the cross runner and a spring nose that enters a hole in the main runner. U.S. Pat. No. 3,677,589 to Roles provides an installation clip which connects with the cross member using mating slots, and connects with the main runner utilizing a concave engaging portion. U.S. Pat. No. 3,596,425 to Kodaras provides a clip member which is received by slots in a specially designed main runner. The clip member then attaches to two cross runners using locking tabs.
The great utility, and in fact, popularity, of these ceiling grid suspension systems is directly related to the ease of their on-site installation. In commercial installations particularly, not only is the ease of installation important, but much consideration is also given to adaptability of the system to differing ceiling constructions and the amount of time required for installation.
Many of the simplest and quickest connections of the prior art are provided by connectors integral with the beams. These, however, are more difficult and expensive to manufacture. The separate connector assemblies, while less expensive to manufacture, often experience problems of poor mechanical connection and lack of stability or rigidity of the connection.
In the Sharp, U.S. Pat. No. 4,494,350, a pair of connectors is employed to interconnect two cross runners with each other and with the main runner. In this patent the two connectors are identical and each is slidably inserted into and locked to the web of one of the cross runners by a pair of dimples and includes a narrower projecting tongue extending through a vertical slot in the web of the main runner that has a hole which receives a connecting tab struck out of the web of the adjoining runner. Because the use of dimples these clips are necessarily made of thinner, more flexible material which may inadvertently become bent or distorted so as to increase difficulties of field assembly. Further, the connector clips of the Sharp patent must each be individually assembled to the runner web, and each runner must be formed with both a dimple receiving aperture and a tongue struck out from the cross runner web at a carefully located point. Thus the assembly of a ceiling suspension system employing the connectors of the Sharp patent is more difficult and more time consuming because of use of two thin and flexible connectors that must be individually installed and connected and may experience undesired flexibility and lack of rigidity in assembled condition.
In the arrangement of the Sharp patent, and in many other prior art arrangements, a full height portion of the connector clip is secured to one end of one of the cross runners, but the portion of the connector clip that projects through the interposed main runner and is connected to the second cross runner is of a lesser height and therefore of greatly decreased strength. Moreover, the connection of the clip to the second cross runner is of less rigidity and less strength. For example, in the Sharp patent, one side of the connector slip is slidably received in upper and lower channels formed in upper and lower flanges of one runner, and, even though the other cross runner is formed with the very same channels, the end of the connector clip which extends through the interposed main runner and is connected to the second runner web does not extend into the channels of the second cross runner but has a greatly decreased height and is connected to the second cross runner solely by a tab and hole. Therefore there is less strength and stability in the connection of the clip to the second cross runner.
Accordingly, it is an object of the present invention to provide a ceiling suspension system and connector clip therefor that avoids or minimizes above mentioned problems.